TABLE 3.

EGF-induced recruitment of the EGFR into coated pits in serum-starved cellsa

Culture conditionsEGFR-positive coated pits (%)EGFR in coated pits (%)
On ice
    Without EGF2.0 ± 1.60.7 ± 0.6
    With EGF33.7 ± 4.513 ± 2.2
At 37°C
    Without EGF2.3 ± 0.51.1 ± 0.5
    With EGF24.0 ± 4.216.7 ± 2.5
  • a By immuno-EM, the number of coated pits and the plasma membrane distribution of the EGFR were quantified in serum-starved HeLa cells incubated with or without EGF (60 ng/ml) for either 1h on ice or 3 min at 37°C. The number of EGFR-positive coated pits is presented as the percentage of the total number of coated pits observed. The EGFR localized to coated pits is presented as the percentage of the total labeling for EGFR found at the plasma membrane. Each data set was derived from three independent labeling experiments ± SD.